#define _CRT_SECURE_NO_WARNINGS 1
#include"List.h"
test1()
{
	LTNode* phead = LTInit();
	return phead;
}

test2()
{
	LTNode* phead = LTInit();
	LTPushBack(phead, 1);
	LTPushBack(phead, 2);
	LTPushBack(phead, 3);
	LTPushBack(phead, 4);
	LTprint(phead);
}

test3()
{
	LTNode* phead = LTInit();
	LTPushFront(phead, 1);
	LTPushFront(phead, 2);
	LTPushFront(phead, 3);
	LTPushFront(phead, 4);
	LTprint(phead);
	//LTLTPopBack(phead);
	//LTPopFront(phead);
	//LTPopFront(phead);
	LTNode* x = LTFind(phead, 1);
	LTNode* y = LTFind(phead, 4);
	//printf("%d ", x->data);
	//printf("%d ", y->data);
	LTInset(x, 8);
	LTInset(y, 9);
	LTprint(phead);
	LTErase(x);
	LTErase(y);
	LTprint(phead);
}
//int main()
//{
//	/*test1();*/
//	/*test2();*/
//	//test3(); 
//	return 0;
//}

#include<stdio.h>
void main()
{
float x, y;
scanf("%f", &x);
if (x < -1)
	y = 1;
else if (x >= -18 & x <= 1)
y = 2 * x + 5;
else
y = 5 * x * x - 1;
printf("%f\n", y);
}